Nuclear Energy Systems

Dear Colleagues,

The Topic “Nuclear Energy Systems” comprises articles reporting original and innovative contributions to the nuclear science and engineering activities aimed at the design of nuclear reactors, from radioisotope power systems for deep space exploration to advanced small and large reactors employing light water, gas, liquid-metal or molten salt coolants, designed not only for electricity generation but also for desalination and/or production of process heat for industrial applications. Authors can submit manuscripts to any MDPI journal participating in the Topic. Published papers will be collected together on the Topic website.

The Topic “Nuclear Energy Systems” includes the following subtopics:

  • Reactor Statics
    • Reactor physics
    • Reactor shielding
    • Radiation and particle transport and detection
  • Reactor Dynamics and Nuclide Depletion/Transmutation
    • Reactor thermal hydraulics
    • Reactor kinetics
    • Reactor control
    • Reactor safety
    • Reactor fuels and fuel cycles
  • Reactor Systems
    • Light water reactors
    • Sodium-cooled reactors
    • Heavy-metal-cooled reactors
    • Gas-cooled reactors
    • Molten-salt reactors
    • Radioisotope power systems
  • Sensitivity Analysis and Uncertainty Quantification with Applications to Nuclear Energy Systems
    • Deterministic and statistical methods for sensitivity analysis
    • Deterministic and statistical methods for uncertainty quantification
    • Predictive modeling: combining experimental and computational information to obtain best-estimate results with reduced predicted uncertainties.

Prof. Dr. Dan Gabriel Cacuci
Prof. Dr. Michael M.R. Williams
Dr. Andrew Buchan
Prof. Dr. Ruixian Fang
Topic Editors

 
 
 
 

Deadline for abstract submissions: 31 January 2022.
Deadline for manuscript submissions: 30 June 2022.

Topic Board

Prof. Dr. Dan Gabriel Cacuci
E-Mail Website
Topic Editor-in-Chief
Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USA
Interests: all areas of nuclear engineering; sensitivity and uncertainty analysis of large-scale systems; predictive modeling by combining experimental and computational information to reduce uncertainties in predicted results
Special Issues and Collections in MDPI journals
Prof. Dr. Michael M.R. Williams
E-Mail Website
Topic Associate Editor-in-Chief
Mechanical Engineering Department, Nuclear Engineering Group, Imperial College of Science, Technology and Medicine, Exhibition Road, SW7 2AZ, UK
Interests: neutron transport theory; stochastic problems related to nuclear reactors; uncertainty analysis via polynomial chaos methods; radionuclide transport in the bio- and geo-spheres; aerosol physics
Dr. Andrew Buchan
E-Mail Website
Topic Associate Editor-in-Chief
School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
Interests: neutron transport; reactor physics; adaptive finite elements; sensitivity analysis
Special Issues and Collections in MDPI journals
Prof. Dr. Ruixian Fang
E-Mail Website
Topic Associate Editor-in-Chief
Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29201, USA
Interests: computational and experimental heat transfer; fluid dynamics; thermal management of large-scale systems; neutron transport theory; sensitivity and uncertainty analysis

Relevant Journals List

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Energies
energies
3.004 4.7 2008 15.92 Days 2000 CHF Submit
Journal of Nuclear Engineering
jne
- - 2020 129.94 Days 1000 CHF Submit
Entropy
entropy
2.524 4.0 1999 16.18 Days 1800 CHF Submit
Symmetry
symmetry
2.713 3.4 2009 13.29 Days 1800 CHF Submit
Sci
sci
- - 2019 0 Days 1200 CHF Submit

Published Papers (3 papers)

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Article
RANS CFD Analysis of Hump Formation Mechanism in Double-Suction Centrifugal Pump under Part Load Condition
Energies 2021, 14(20), 6815; https://0-doi-org.brum.beds.ac.uk/10.3390/en14206815 - 18 Oct 2021
Abstract
The RANS (Reynolds-averaged Navier–Stokes equations) with CFD (Computational Fluid Dynamics) simulation method is used to analyze the head hump formation mechanism in the double-suction centrifugal pump under a part load condition. The purpose is to establish a clear connection between the head hump [...] Read more.
The RANS (Reynolds-averaged Navier–Stokes equations) with CFD (Computational Fluid Dynamics) simulation method is used to analyze the head hump formation mechanism in the double-suction centrifugal pump under a part load condition. The purpose is to establish a clear connection between the head hump and the microcosmic flow field structure, and reveal the influence mechanism between them. It is found that the diffuser stall causes a change in the impeller capacity for work, and this is the most critical reason for hump formation. The change in the hydraulic loss of volute is also a reason for hump, and it is analyzed using the energy balance equation. The hump formation mechanism has not been fully revealed so far. This paper found the most critical flow structure inducing hump and revealed its inducing mechanism, and greatly promoted the understanding of hump formation. The impeller capacity for work is analyzed using torque and rotational speed directly, avoiding large error caused by the Euler head formula, greatly enhancing the accuracy of establishing the connection between the impeller capacity for work and the coherent structure in the flow field under a part load condition. When a pump is running in the hump area, a strong vibration and noise are prone to occur, endangering the pump safety and reliability, and even the pump start and the transition of different working conditions may be interrupted. Revealing the hump formation mechanism provides a key theoretical basis for suppressing hump. Hump problems are widespread in many kinds of pumps, causing a series of troubles and hazards. The analysis method in this paper also provides a reference for other pumps. Full article
(This article belongs to the Topic Nuclear Energy Systems)
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Article
Experimental Validation of Flow Uniformity Improvement by a Perforated Plate in the Heat Exchanger of SFR Steam Generator
Energies 2021, 14(18), 5846; https://0-doi-org.brum.beds.ac.uk/10.3390/en14185846 - 15 Sep 2021
Abstract
The steam generator in a nuclear power plant is a type of heat exchanger in which heat transfer occurs from the hot fluid in multiple channels to the cold fluid. Therefore, a uniform flow over multiple channels is necessary to improve heat exchanger [...] Read more.
The steam generator in a nuclear power plant is a type of heat exchanger in which heat transfer occurs from the hot fluid in multiple channels to the cold fluid. Therefore, a uniform flow over multiple channels is necessary to improve heat exchanger efficiency. The study aims at experimentally investigating the improvement of flow uniformity by the perforated plate in the heat exchanger used for a sodium-cooled fast reactor stream generator. A 1/4-scale experimental model for one heat exchanger unit with 33 × 66 channels was manufactured. The working fluid was water. A perforated plate was systematically designed using numerical simulations to improve the flow uniformity over the 33 × 66 channels. As a result, the flow uniformity greatly improved at a slight cost of pressure drop. To validate the numerical results, planar particle image velocimetry measurements were performed on the selected planes in the inlet and outlet headers. The experimental velocity profiles near the exits of the channels were compared with numerical simulation data. The experimental profiles agreed with the numerical data well. Both the numerical simulation and the experimental results showed a slight increase in pressure drop, despite significant improvement in the flow uniformity. Full article
(This article belongs to the Topic Nuclear Energy Systems)
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Article
Fourth-Order Adjoint Sensitivity and Uncertainty Analysis of an OECD/NEA Reactor Physics Benchmark: I. Computed Sensitivities
J. Nucl. Eng. 2021, 2(3), 281-308; https://0-doi-org.brum.beds.ac.uk/10.3390/jne2030024 - 24 Aug 2021
Cited by 1
Abstract
This work extends the investigation of higher-order sensitivity and uncertainty analysis from 3rd-order to 4th-order for a polyethylene-reflected plutonium (PERP) OECD/NEA reactor physics benchmark. Specifically, by applying the 4th-order comprehensive adjoint sensitivity analysis methodology (4th-CASAM) to the PERP benchmark, this work presents the [...] Read more.
This work extends the investigation of higher-order sensitivity and uncertainty analysis from 3rd-order to 4th-order for a polyethylene-reflected plutonium (PERP) OECD/NEA reactor physics benchmark. Specifically, by applying the 4th-order comprehensive adjoint sensitivity analysis methodology (4th-CASAM) to the PERP benchmark, this work presents the numerical results of the most important 4th-order sensitivities of the benchmark’s total leakage response with respect to the benchmark’s 180 microscopic total cross sections, which includes 180 4th-order unmixed sensitivities and 360 4th-order mixed sensitivities corresponding to the largest 3rd-order ones. The numerical results obtained in this work reveal that the number of 4th-order relative sensitivities that have large values (e.g., greater than 1.0) is far greater than the number of important 1st-, 2nd- and 3rd-order sensitivities. The majority of those large sensitivities involve isotopes 1H and 239Pu contained in the PERP benchmark. Furthermore, it is found that for most groups of isotopes 1H and 239Pu of the PERP benchmark, the values of the 4th-order relative sensitivities are significantly larger than the corresponding 1st-, 2nd- and 3rd-order sensitivities. The overall largest 4th-order relative sensitivity S(4)σt,6g=30,σt,6g=30,σt,6g=30,σt,6g=30=2.720×106 is around 291,000 times, 6350 times and 90 times larger than the corresponding largest 1st-order, 2nd-order and 3rd-order sensitivities, respectively, and the overall largest mixed 4th-order relative sensitivity S(4)σt,630,σt,630,σt,630,σt,530=2.279×105 is also much larger than the largest 2nd-order and 3rd-order mixed sensitivities. The results of the 4th-order sensitivities presented in this work have been independently verified with the results obtained using the well-known finite difference method, as well as with the values of the corresponding symmetric 4th-order sensitivities. The 4th-order sensitivity results obtained in this work will be subsequently used on the 4th-order uncertainty analysis to evaluate their impact on the uncertainties they induce in the PERP leakage response. Full article
(This article belongs to the Topic Nuclear Energy Systems)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

To be submitted to Energies:

1: Optimized Adjoint Sensitivity Analysis using Adjoint Guided Mesh Adaptivity Applied to Neutron Detector Response Calculations

Andrew Buchan 1,*, Dan G. Cacuci 2, Steven Dargaville 3 and Christopher C. Pain 3

Abstract: This article presents a novel method that combines adaptive mesh resolution with sensitivity analysis for the efficient computation of neutron/photon dose calculations with estimates of sensitivities with respect to material cross-section data. Estimates of the dose are obtained from the solution to the Boltzmann transport equation discretized in space using unstructured finite elements with adaptive mesh resolution. The estimates of all sensitivities are obtained through the single solution of the associated adjoint equations. However, importantly, the same adjoint solution is also used to guide the mesh adaptivity to calculate the dose optimally. The entire process of optimally adapting the mesh and obtaining sensitivity estimates only requires a single computation of the forward and adjoint solutions, which makes it a highly efficient solution process. The Maynard problem is used to demonstrate the capability of the method where sensitivities of neutron doses are calculated with respect to the material cross-sections. It is demonstrated that the spatial variation in cross-section sensitivities can be more efficiently and accurately predicted by comparison to uniform mesh refinement.

To be submitted to JNE:

2: Fourth-Order Adjoint Sensitivity and Uncertainty Analysis of an OECD/NEA Reactor Physics Benchmark: I. Computed Sensitivities

Ruixian Fang 1,* and Dan G. Cacuci 2

Abstract: This work extends the investigation of higher-order sensitivity and uncertainty analysis to 4th-order for a polyethylene-reflected plutonium (PERP) OECD/NEA reactor physics benchmark. Specifically, by applying the 4th-order comprehensive adjoint sensitivity analysis methodology (4th-CASAM) to the PERP benchmark, this work presents the numerical results of the most important 4th-order sensitivities, of the benchmark’s total leakage response with respect to the benchmark’s 180 microscopic total cross sections, which includes 180 4th-order unmixed sensitivities and 360 4th-order mixed sensitivities corresponding to the largest 3rd-order ones. The numerical results obtained in this work revealed that the number of 4th-order relative sensitivities that have large values (e.g., greater than 1.0) is far greater than the number of important 1st-, 2nd- and 3rd-order sensitivities. Majority of those large sensitivities involve isotopes 1H and 239Pu contained in the PERP benchmark. Also, it was found that for most groups of isotopes 1H and 239Pu of the PERP benchmark, the values of the 4th-order relative sensitivities are significantly larger than the corresponding 1st-, 2nd- and 3rd-order sensitivities. The overall largest 4th-order relative sensitivity  is around 291,000 times, 6,350 times and 90 times larger than the corresponding largest 1st-order, 2nd-order and 3rd-order sensitivities, respectively. The overall largest mixed 4th-order relative sensitivity  is also much larger than the largest 2nd-order and 3rd-order mixed sensitivities. The results of the 4th-order sensitivities presented in this work have been independently verified with the results obtained using the well-known finite difference method, as well as with the values of the corresponding symmetric 4th-order sensitivities. The 4th-order sensitivities results obtained in this work will be subsequently used on the 4th-order uncertainty analysis to evaluate their impact on the uncertainties they induce in the PERP leakage response.

To be submitted to JNE:

3: Fourth-Order Adjoint Sensitivity and Uncertainty Analysis of an OECD/NEA Reactor Physics Benchmark: II. Computed Response Uncertainties

Ruixian Fang 1,* and Dan G. Cacuci 2

Abstract: This work quantifies the contributions of the important fourth-order sensitivities to the polyethylene-reflected plutonium (PERP) OECD/NEA reactor physics benchmark’s leakage response distribution moments (i.e., expected value, variance, and skewness), and compares these contributions to those stemming from the corresponding first-, second- and third-order sensitivities of the PERP benchmark’s leakage response with respect to the 180 microscopic total cross sections. The impact of the fourth-order sensitivities is discussed.

To be submitted to Energies:

4: The nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Response-Coupled Forward/Adjoint Linear Systems (nth-CASAM-L): I. Mathematical Framework

Dan G. Cacuci 1,*

Abstract: The computational model of a physical system generally comprises independent variables (e.g., space, time, etc.), dependent variables (aka “state functions”; e.g., temperature, mass, momentum, etc.) and various imperfectly known parameters (appearing in correlations, coordinates of physical boundaries, etc.), which are all interrelated by equations that usually represent conservation laws. The quantities of interest (called “responses”) produced by the computational model of a linear physical systems can depend on the model’s imperfectly known parameters through both the forward and the adjoint state functions that describe the respective physical system. The effects of the imperfectly known parameters on the model’s responses are quantified by the sensitivities (i.e., functional derivatives) of the model responses with respect to the model parameters. This work presents the mathematical underpinnings of the nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Linear Systems (abbreviated as “nth-CASAM-L”), which is conceived for obtaining the exact expressions of arbitrarily-high-order (nth-order) sensitivities of a generic system response with respect to all of the parameters underlying the respective forward/adjoint systems, so as to enable their most efficient computation. The nth-CASAM is developed in linearly increasing higher-dimensional Hilbert spaces, as opposed to exponentially increasing “parameter-dimensional” spaces in which response sensitivities are computed by other methods, thus providing the basis for significant future advances towards overcoming the “curse of dimensionality,” not only in sensitivity analysis but also in uncertainty quantification and predictive modeling.

To be submitted to Energies:

5: The nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Response-Coupled Forward/Adjoint Linear Systems (nth-CASAM-L): II. Illustrative Application to Radiation Transport

Dan G. Cacuci 1,*

Abstract: The application of the nth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Linear Systems (“nth-CASAM-L”) is illustrated in this work by considering a paradigm radiation transport and detection model. It is shown that the expressions for the high-order sensitivities obtained by applying the nth-CASAM-L are the exact and can be computed in linearly, as opposed to exponentially, increasing number of computations, thus overcoming to a decisive extent the curse of dimensionality.

To be submitted to JNE:

6: The Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems (4th-CASAM-N): Mathematical Framework and Illustrative Application to Nuclear Heat Transfer

Dan G. Cacuci 1,*

Abstract: This work presents the Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology for Nonlinear Systems (4th-CASAM-N), which enables the efficient computation of the exact expressions of the 1st-, 2nd-, 3rd- and 4th-order sensitivities (i.e., functional derivatives) of a generic response (i.e., result of interest) produced by the computational model of a nonlinear physical system with respect to all of the model’s parameters, which are seldom, if ever, perfectly known. For nonlinear systems, the 4th-CASAM-N presented in this work is the only practically implementable methodology for obtaining and subsequently computing the exact expressions (i.e., free of methodologically-introduced approximations) of the 1st-, 2nd, 3rd- and 4th-order sensitivities, thus enabling comparisons of the relative values of the sensitivities of various order, to assess quantitatively which sensitivities are important and which may actually be neglected. The 4th-CASAM-N provides the essential foundation in the quest to overcome the “curse of dimensionality” in sensitivity analysis, uncertainty quantification and predictive modeling. Ongoing work aims at generalizing the 4th-CASAM-N, conceiving a general methodology for the practical, efficient, and exact computation of the nth-order (i.e., arbitrarily-high order) sensitivities of responses to model parameters for nonlinear systems.

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